Re: [PATCH 9/8] middle-end: Allow build_popcount_expr to use an IFN

[Andrew Carlotti <andrew.carlotti@arm.com>]

Hi Richard

I accidentally pushed this patch earlier in the mistaken belief that
you'd already approved it. It looks uncontroversial to me - it just adds
IFN support to build_popcount_expr, analogous to the changes you
suggested and approved for build_cltz_expr (and adjusts testcases
accordingly). I might have incorporated it into an earlier patch in this
series, if I hadn't already pushed that earlier patch.

Is this OK to leave in master now?

Thanks,
Andrew

On Thu, Dec 22, 2022 at 05:43:21PM +0000, Andrew Carlotti via Gcc-patches wrote:
> Bootstrapped and regression tested on aarch64-unknown-linux-gnu and
> x86_64-pc-linux-gnu - ok to merge?
> 
> gcc/ChangeLog:
> 
> 	* tree-ssa-loop-niter.cc (build_popcount_expr): Add IFN support.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/tree-ssa/pr86544.C: Add .POPCOUNT to tree scan regex.
> 	* gcc.dg/tree-ssa/popcount.c: Likewise.
> 	* gcc.dg/tree-ssa/popcount2.c: Likewise.
> 	* gcc.dg/tree-ssa/popcount3.c: Likewise.
> 	* gcc.target/aarch64/popcount4.c: Likewise.
> 	* gcc.target/i386/pr95771.c: Likewise, and...
> 	* gcc.target/i386/pr95771-2.c: ...split int128 test from above,
> 	since this would emit just a single IFN if a TI optab is added.
> 
> ---
> 
> diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr86544.C b/gcc/testsuite/g++.dg/tree-ssa/pr86544.C
> index ef438916a8019320564f444ace08e2f4b4190684..50befb36bac75de1cfa282e38358278b3288bd1c 100644
> --- a/gcc/testsuite/g++.dg/tree-ssa/pr86544.C
> +++ b/gcc/testsuite/g++.dg/tree-ssa/pr86544.C
> @@ -12,5 +12,5 @@ int PopCount (long b) {
>      return c;
>  }
>  
> -/* { dg-final { scan-tree-dump-times "__builtin_popcount" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "__builtin_popcount|\\.POPCOUNT" 1 "optimized" } } */
>  /* { dg-final { scan-tree-dump-times "if" 0 "phiopt4" } } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/popcount.c b/gcc/testsuite/gcc.dg/tree-ssa/popcount.c
> index b4694109411a4631697463519acbe7d9df65bf6e..efd906a0f5447f0beb3752eded3756999b02e6e6 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/popcount.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/popcount.c
> @@ -39,4 +39,4 @@ void PopCount3 (long b1) {
>        }
>  }
>  
> -/* { dg-final { scan-tree-dump-times "__builtin_popcount" 3 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "__builtin_popcount|\\.POPCOUNT" 3 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/popcount2.c b/gcc/testsuite/gcc.dg/tree-ssa/popcount2.c
> index ef73e345573de721833e98e89c252640a55f7c60..ae38a329bd4d868a762300d3218d68864c0fc4be 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/popcount2.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/popcount2.c
> @@ -26,4 +26,4 @@ int main()
>    return 0;
>  }
>  
> -/* { dg-final { scan-tree-dump-times "__builtin_popcount" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "__builtin_popcount|\\.POPCOUNT" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c b/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
> index ef438916a8019320564f444ace08e2f4b4190684..50befb36bac75de1cfa282e38358278b3288bd1c 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
> @@ -12,5 +12,5 @@ int PopCount (long b) {
>      return c;
>  }
>  
> -/* { dg-final { scan-tree-dump-times "__builtin_popcount" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "__builtin_popcount|\\.POPCOUNT" 1 "optimized" } } */
>  /* { dg-final { scan-tree-dump-times "if" 0 "phiopt4" } } */
> diff --git a/gcc/testsuite/gcc.target/aarch64/popcount4.c b/gcc/testsuite/gcc.target/aarch64/popcount4.c
> index ee55b2e335223053ca024e95b7a13aa4af32550e..8aa15ff018d4b5fc6bb59e52af20d5c33cea2ee0 100644
> --- a/gcc/testsuite/gcc.target/aarch64/popcount4.c
> +++ b/gcc/testsuite/gcc.target/aarch64/popcount4.c
> @@ -11,4 +11,4 @@ int PopCount (long b) {
>      return c;
>  }
>  
> -/* { dg-final { scan-tree-dump-times "__builtin_popcount" 0 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "__builtin_popcount|\\.POPCOUNT" 0 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr95771-2.c b/gcc/testsuite/gcc.target/i386/pr95771-2.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..1db9dc94d0b66477667624012221d6844c141a26
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr95771-2.c
> @@ -0,0 +1,17 @@
> +/* PR tree-optimization/95771 */
> +/* { dg-do compile } */
> +/* { dg-require-effective-target int128 } */
> +/* { dg-options "-O2 -mpopcnt -fdump-tree-optimized" } */
> +/* { dg-final { scan-tree-dump " = __builtin_popcount| = \\.POPCOUNT" "optimized" } } */
> +
> +int
> +corge (unsigned __int128 x)
> +{
> +  int i = 0;
> +  while (x)
> +    {
> +      x &= x - 1;
> +      ++i;
> +    }
> +  return i;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr95771.c b/gcc/testsuite/gcc.target/i386/pr95771.c
> index d7b67017800b705b9854f561916c20901ea76803..d41be445f4a68613a082b8956fea3ceaf33d7e0f 100644
> --- a/gcc/testsuite/gcc.target/i386/pr95771.c
> +++ b/gcc/testsuite/gcc.target/i386/pr95771.c
> @@ -1,8 +1,7 @@
>  /* PR tree-optimization/95771 */
>  /* { dg-do compile } */
>  /* { dg-options "-O2 -mpopcnt -fdump-tree-optimized" } */
> -/* { dg-final { scan-tree-dump-times " = __builtin_popcount" 6 "optimized" { target int128 } } } */
> -/* { dg-final { scan-tree-dump-times " = __builtin_popcount" 4 "optimized" { target { ! int128 } } } } */
> +/* { dg-final { scan-tree-dump-times " = __builtin_popcount| = \\.POPCOUNT" 4 "optimized" } } */
>  
>  int
>  foo (unsigned char x)
> @@ -51,17 +50,3 @@ qux (unsigned long long x)
>      }
>    return i;
>  }
> -
> -#ifdef __SIZEOF_INT128__
> -int
> -corge (unsigned __int128 x)
> -{
> -  int i = 0;
> -  while (x)
> -    {
> -      x &= x - 1;
> -      ++i;
> -    }
> -  return i;
> -}
> -#endif
> diff --git a/gcc/tree-ssa-loop-niter.cc b/gcc/tree-ssa-loop-niter.cc
> index 9c2f9f3d5f6205bb5e7f490257800c660fdd0b8d..cc53b27329f8518bc2cacef1830768a140331b31 100644
> --- a/gcc/tree-ssa-loop-niter.cc
> +++ b/gcc/tree-ssa-loop-niter.cc
> @@ -2033,11 +2033,18 @@ static tree
>  build_popcount_expr (tree src)
>  {
>    tree fn;
> +  bool use_ifn = false;
>    int prec = TYPE_PRECISION (TREE_TYPE (src));
>    int i_prec = TYPE_PRECISION (integer_type_node);
>    int li_prec = TYPE_PRECISION (long_integer_type_node);
>    int lli_prec = TYPE_PRECISION (long_long_integer_type_node);
> -  if (prec <= i_prec)
> +
> +  tree utype = unsigned_type_for (TREE_TYPE (src));
> +  src = fold_convert (utype, src);
> +
> +  if (direct_internal_fn_supported_p (IFN_POPCOUNT, utype, OPTIMIZE_FOR_BOTH))
> +    use_ifn = true;
> +  else if (prec <= i_prec)
>      fn = builtin_decl_implicit (BUILT_IN_POPCOUNT);
>    else if (prec == li_prec)
>      fn = builtin_decl_implicit (BUILT_IN_POPCOUNTL);
> @@ -2046,12 +2053,11 @@ build_popcount_expr (tree src)
>    else
>      return NULL_TREE;
>  
> -  tree utype = unsigned_type_for (TREE_TYPE (src));
> -  src = fold_convert (utype, src);
> -  if (prec < i_prec)
> -    src = fold_convert (unsigned_type_node, src);
>    tree call;
> -  if (prec == 2 * lli_prec)
> +  if (use_ifn)
> +      call = build_call_expr_internal_loc (UNKNOWN_LOCATION, IFN_POPCOUNT,
> +					   integer_type_node, 1, src);
> +  else if (prec == 2 * lli_prec)
>      {
>        tree src1 = fold_convert (long_long_unsigned_type_node,
>  				fold_build2 (RSHIFT_EXPR, TREE_TYPE (src),
> @@ -2064,7 +2070,12 @@ build_popcount_expr (tree src)
>        call = fold_build2 (PLUS_EXPR, integer_type_node, call1, call2);
>      }
>    else
> -    call = build_call_expr (fn, 1, src);
> +    {
> +      if (prec < i_prec)
> +	src = fold_convert (unsigned_type_node, src);
> +
> +      call = build_call_expr (fn, 1, src);
> +    }
>  
>    return call;
>  }